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Bluetooth and "apps" for basic devices?

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I have been playing with a list of little projects lately and they all seem to need the same things, a display, some basic applied math, and logged data points or send/receive of basic switching functions.

I have never written a phone app but there is literally a bluetooth device and app on every corner in america now and I feel both lost and behind because I don't know how to get started! Can someone guide me to the right place, site, documents, etc?

I will try to explain one of my devices just for an example.
I need to setup a device to test and monitor the temperature of something. I just need to build a basic device with a uC and program it to test the temp at say every 5min, then send that data via bluetooth. If the bluetooth connection is not available, simply retain in memory until connection is enabled, etc. Probably missing a few things there, just getting an idea.

I would need to set the time on the device so I would like to use a phone app to set the clock. As part of the phone app, all the data points would just need put into a basic excel sheet or something for mapping.

I would like to be able to program and setup the device such as test intervals, max tests, max time, etc, with a phone app so no display is needed on the device.

Help please!

Les Jones

Well-Known Member
Most Helpful Member
Hi fastline,
There is a DRO (Digital position readout for machine tools.) design that runs on an Android tablet. I think I have seen the source code somewhere on this site. This might give you enough of an idea about writing your own code to do what you want. The data is sent to the app via Bluetooth as a string of ASCII characters so this part of the code could be used. I have used the app without modification to display the output from a Wixey type angle gauge without any modification of the app. This shows an android tablet displaying data from a Wixey type angle gauge. You could possibly use the app as it stands to start testng your temperature sensor. I have buit a unit that may do part of what you want using a DHT22 (Temperature and humidity sensor.) and a PIC12F1822. It outputs the data a a serial ASCII string. (I use this with an HC-12 radio module which has a much longer range than Bluetooth. I can give you the schematic and source code (In assembler.) if it is any help.

Edit, I have found the link for the DRO source code.

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